Cells as factories for humanized encapsulation

Biocompatibility is of paramount importance for drug delivery, tumor labeling, and in vivo application of nanoscale bioprobes. Until now, biocompatible surface processing has typically relied on PEGylation and other surface coatings, which, however, cannot minimize clearance by macrophages or the renal system but may also increase the risk of chemical side effects. Cell membranes provide a generic and far more natural approach to the challenges of encapsulation and delivery in vivo. Here we harness for the first time living cells as "factories" to manufacture cell membrane capsules for encapsulation and delivery of drugs, nanoparticles, and other biolabels. Furthermore, we demonstrate that the built-in protein channels of the new capsules can be utilized for controlled release of encapsulated reagents.     

Epoxidized soy bean oil (ESBO) migrating from the gaskets of lids into food packed in glass jars

Epoxidized soy bean oil (ESBO) was determined in foods packed in glass jars closed by lids with a poly(vinyl chloride) (PVC) gasket. The methyl ester of a diepoxy linoleic acid isomer was measured, using transesterification directly in the homogenized food and on-line HPLC-GC-FID analysis. Infant foods from the Swiss market consisting of vegetables, potato and rice or muesli with fruits and berries contained less than 7 mg/kg ESBO, but meat (its fat?) strongly increased ESBO migration up to 86 mg/kg. Some 12% of the products exceeded 15 mg/kg. Austrian and Norwegian samples gave similar results. Edible oil strongly extracts the ESBO from the gasket in food contact within a few weeks. Since this part of the gasket on average contained 91 mg ESBO, the legal limit is likely to be far exceeded whenever the food contains free oil contacting the gasket, such as oily sauces or vegetables and fish in oil. In fact, the mean ESBO concentration in 86 samples was 166 mg/kg, with a maximum of 580 mg/kg.     

Synthesis of pyrraline reference material

A simplified and improved method is described for the preparation of pyrraline, a lysine derivative from the advanced Maillard reaction and potential indicator for heat treatment of foods. The compound was obtained in a high degree of purity and with a yield of 31% fromN -t-butyloxycarbonyl-L-lysine after heating with 3-deoxy-D-erythro-hexos-2-ulose for 2 h at 70°C in the dry state, preparative fractionation of the resultingN -t-butyloxycarbonyl pyrraline with reverse-phase liquid chromatography and final deprotection of the intermediate compound with acetic acid.     

How much reducing sugar may potatoes contain to avoid excessive acrylamide formation during roasting and baking?

For many consumers, potatoes fried or roasted in professional or private kitchens are the most important source of exposure to acrylamide. Acrylamide formation can be reduced by appropriate preparation techniques, but suitable potatoes are a prerequisite. The tendency of potato to form acrylamide can be approximated by the content of reducing sugar. Roast potatoes (hash browns, Rösti) and oven-fried potatoes (Bratkartoffeln) were prepared to optimum culinary quality regarding crispiness and then evaluated in terms of browning, roasting flavor and acrylamide content. Preparation procedures were optimized to produce a minimum of acrylamide. It is concluded that potatoes with less than 0.2 g/kg fresh weight fructose and glucose are not suitable for roasting (insufficient browning and flavor), while roasted products of minimum crispiness prepared from potatoes with more than 1 g/kg reducing sugar contain more than 500 µg/kg acrylamide. It is proposed that potatoes which may be used for roasting and frying should contain less than 1 g/kg fresh weight of reducing sugar. This can easily be fulfilled with the most important potato cultivars grown in Switzerland, but presupposes that potatoes are no longer stored at 4 °C.     

Food security in Tanzania: the challenge of rapid urbanisation

Urbanisation in Tanzania is proceeding apace. This article seeks to identify the challenge posed by rapid urbanisation for food security in Tanzania to 2030, the Sustainable Development Goals horizon. It is hypothesized that urban food security largely depends on the food supply systems and the rural food production potential. The analysis of these interlinkages is based on secondary macro data and own primary micro data. Tanzania has done well to achieve broad self-sufficiency in basic foodstuffs to date, but rapid urbanisation will pose a severe future challenge as regards food security, particularly for the disadvantaged poorer people of the towns and cities in terms of food affordability, stability and food safety. Whether Tanzania can avoid future deterioration in urban food security will depend on how responsive and resilient the urban food supply systems prove to be in the face of continuing urban growth, changing consumption patterns, weak rural–urban food supply linkages and production constraints in the smallholder farming sector.     

Elucidation of the biosynthesis and degradation of allantofuranone by isotopic labelling and fermentation of modified precursors

Feeding experiments with the ascomycete Allantophomopsis lycopodina indicated that the potent fungistatic allantofuranone is biosynthesized from phenylalanine. Further experiments with synthetic precursors gave evidence that the naturally occurring polyporic acid serves as a key intermediate in the biosynthesis. In addition to the formation of allantofuranone, its abiotic and metabolic degradation were investigated.     

Viscosity‐molecular weight relationship for cellulose solutions in either NMMO monohydrate or cuen

The intrinsic viscosities, [η], of nine cellulose samples, with molar masses from 50 × 10³ to 1 390 × 10³ were determined in the solvents NMMO*H₂O (N‐methyl morpholin N‐oxide hydrate) at 80°C and in cuen (copper II‐ethlenediamine) at 25°C. The evaluation of these results with respect to the Kuhn–Mark–Houwink relations shows that the data for NMMO*H₂O fall on the usual straight line in the double logarithmic plots only for M ≤ 158 10³; the corresponding [η]/M relation reads log ([η]/mL g⁻¹) = –1.465 + 0.735 log M. Beyond that molar mass [η] remains almost constant up to M ≈ 10⁶ and increases again thereafter. In contrast to NMMO*H₂O the cellulose solutions in cuen behave normal and the Kuhn–Mark–Houwink relation reads log ([η]/mL g⁻¹) = −1.185 + 0.735 log M. Possible reasons for the dissimilarities of the behavior of cellulose in these two solvents are being discussed. The comparison of three different methods for the determination of [η] from viscosity measurements at different polymer concentrations, c, demonstrates the advantages of plotting the natural logarithm of the relative viscosities as a function of c. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of compression on the performance of a HT-PEM fuel cell

This paper shows by thorough electrochemical investigation that (1) the performances of high-temperature polymer electrolyte fuel cell membrane electrode assemblies of three suppliers are differently affected by compressive forces. (2) Membrane thickness reduction by compressive pressure takes place less than expected. (3) A contact pressure cycling experiment is a useful tool to distinguish the impact of compression on the contact resistances bipolar plate/gas diffusion layer (GDL) and GDL/catalytic layer. A detailed visual insight into the structural effects of compressive forces on membrane and gas diffusion electrode (GDE) is obtained by micro-computed X-ray tomography (μ-CT). μ-CT imaging confirms that membrane and GDEs undergo severe mechanical stress resulting in performance differences. Irreversible GDL deformation behavior and pinhole formation by GDL fiber penetration into the membrane could be observed.     

Modulation of Aphid Alarm Pheromone Emission of Pea Aphid Prey by Predators

Recent studies on animal alarm signaling have shown that alarm calls generally are not uniform, but may vary depending on the type and intensity of threat. While alarm call variability has been studied intensively in birds and mammals, little is known about such variation in insects. We investigated variability in alarm signaling in aphids, group-living insect herbivores. Under attack, aphids release droplets containing a volatile alarm pheromone, (E)-β-farnesene (EBF), that induces specific escape behavior in conspecifics. We used a handheld gas chromatograph (zNose?), which allows real-time volatile analysis, to measure EBF emission by pea aphids, Acyrthosiphon pisum, under attack from different predators, lacewing or ladybird larvae. We demonstrate that aphid alarm signaling is affected by the predator species attacking. Ladybirds generally elicited smaller EBF emission peaks and consumed aphids more quickly, resulting in lower total EBF emission compared to lacewing attacks. In 52 % of the replicates with lacewings and 23 % with ladybirds, no EBF was detectable in the headspace, although aphids secreted cornicle droplets after attack. We, therefore, examined EBF amounts contained in these droplets and the aphid body. While all aphid bodies always contained EBF, many secreted droplets did not. Our experiments show that alarm signaling in insects can be variable, and both the attacker as well as the attacked may affect alarm signal variation. While underlying mechanisms of such variation in aphid-predator interactions need to be investigated in more detail, we argue that at least part of this variation may be adaptive for the predator and the aphid.     

And Yet It Moves: Oxidation of the Nuclear Autoantigen La/SS-B Is the Driving Force for Nucleo-Cytoplasmic Shuttling

Decades ago, we and many other groups showed a nucleo-cytoplasmic translocation of La protein in cultured cells. This shuttling of La protein was seen after UV irradiation, virus infections, hydrogen peroxide exposure and the Fenton reaction based on iron or copper ions. All of these conditions are somehow related to oxidative stress. Unfortunately, these harsh conditions could also cause an artificial release of La protein. Even until today, the shuttling and the cytoplasmic function of La/SS-B is controversially discussed. Moreover, the driving mechanism for the shuttling of La protein remains unclear. Recently, we showed that La protein undergoes redox-dependent conformational changes. Moreover, we developed anti-La monoclonal antibodies (anti-La mAbs), which are specific for either the reduced form of La protein or the oxidized form. Using these tools, here we show that redox-dependent conformational changes are the driving force for the shuttling of La protein. Moreover, we show that translocation of La protein to the cytoplasm can be triggered in a ligand/receptor-dependent manner under physiological conditions. We show that ligands of toll-like receptors lead to a redox-dependent shuttling of La protein. The shuttling of La protein depends on the redox status of the respective cell type. Endothelial cells are usually resistant to the shuttling of La protein, while dendritic cells are highly sensitive. However, the deprivation of intracellular reducing agents in endothelial cells makes endothelial cells sensitive to a redox-dependent shuttling of La protein.